Research regarding the distribution and structure of fungal communities in caves is lacking. The current study examines fungal communities in Kartchner Caverns, a mineralogically diverse cave located in the Whetstone Mountains, Arizona, USA. The first study examines culturable fungal diversity from speleothem surfaces. Twenty-one fungal genera represented by 43 genotypes and 53 distinct morphological taxonomic units (MTU) were recovered from 15 speleothems. Analysis of DGGE profiles indicated a significant effect of sampling site on community structure. The second study examined fungal diversity from speleothem and rock wall surfaces using the 454 FLX Titanium sequencing platform using the rDNA internal transcribed spacer 1 (ITS1) as a genetic marker. Fungal diversity was estimated and compared between speleothem and rock wall surfaces and its variation with distance from the natural entrance of the cave was quantified. Effects of environmental factors and nutrient concentrations in speleothem drip water at different sample sites on fungal diversity were also examined. Sequencing revealed 2219 fungal operational taxonomic units (OTUs) at 95% similarity. Speleothems supported a higher fungal richness and diversity than rock walls, but community membership and the taxonomic distribution of fungal OTUs did not differ significantly. OTU richness and diversity were negatively correlated with distance from the natural cave entrance. Community membership and taxonomic distribution of fungal OTUs differed significantly between the front and back of the cave. There was no observed effect of drip water nutrient concentration on fungal community structure. The third study examined fungal community structure from bat guano over the course of a year. There was no significant difference in fungal OTU richness, diversity, or community membership and taxonomic affiliations among sampling times. There were no significant differences in nutrient concentrations of guano samples among sampling times. Nutrient concentration did have a significant effect on community structure, especially the level of nitrogen and calcium.

<p>The rationale of this study is to apply light stable isotope chemistry towards investigations that require temporally high-resolution data. High-resolution (or high sampling frequency) data sets, are critical for testing environmental and/or paleoenvironmental hypotheses that seek to explain processes occurring over rapid or short time intervals. The investigation of climate variation (e.g., seasonality, El Niño, deglaciation), animal migration and physiology, and disturbance ecology (e.g., fire, flooding) benefits from the recovery of proxy information at decadal to subannual resolutions. The type of material used also dictates a spatial scale. Herein are presented four studies that utilize high-resolution light stable isotope profiles with contrasting temporal and spatial scales. The first study employs advances in three-dimensional computer-controlled micromilling to recover ~daily to weekly deposited carbonate from small (~1 cm) mollusc shells. Stable oxygen isotope values from freshwater mollusc shells are predictably related to the local environment of growth using previously published temperature-fractionation relationships, providing a paleoclimate record of temperature and precipitation. The second study investigates variation in stable carbon isotope values from Aplodinotus grunniens otoliths, for which high-resolution patterns were critical in assessing metabolic rate as the governing control. The third study employs high-resolution stable oxygen and carbon isotope values to determine chinook salmon (Oncorhynchus tshawytscha) seasonal and ontogenetic migration in Lake Ontario and its tributaries. Lastly, high-resolution stable hydrogen and carbon isotope values of chitin derived from Mexican free-tailed bat (Tadarida brasiliensis) guano are presented, providing a record of abrupt climate change. Thus, this thesis reports on promising new research avenues for paleoclimatology, paleoecology, and modern ecology.

<p>The rationale of this study is to apply light stable isotope chemistry towards investigations that require temporally high-resolution data. High-resolution (or high sampling frequency) data sets, are critical for testing environmental and/or paleoenvironmental hypotheses that seek to explain processes occurring over rapid or short time intervals. The investigation of climate variation (e.g., seasonality, El Niño, deglaciation), animal migration and physiology, and disturbance ecology (e.g., fire, flooding) benefits from the recovery of proxy information at decadal to subannual resolutions. The type of material used also dictates a spatial scale. Herein are presented four studies that utilize high-resolution light stable isotope profiles with contrasting temporal and spatial scales. The first study employs advances in three-dimensional computer-controlled micromilling to recover ~daily to weekly deposited carbonate from small (~1 cm) mollusc shells. Stable oxygen isotope values from freshwater mollusc shells are predictably related to the local environment of growth using previously published temperature-fractionation relationships, providing a paleoclimate record of temperature and precipitation. The second study investigates variation in stable carbon isotope values from Aplodinotus grunniens otoliths, for which high-resolution patterns were critical in assessing metabolic rate as the governing control. The third study employs high-resolution stable oxygen and carbon isotope values to determine chinook salmon (Oncorhynchus tshawytscha) seasonal and ontogenetic migration in Lake Ontario and its tributaries. Lastly, high-resolution stable hydrogen and carbon isotope values of chitin derived from Mexican free-tailed bat (Tadarida brasiliensis) guano are presented, providing a record of abrupt climate change. Thus, this thesis reports on promising new research avenues for paleoclimatology, paleoecology, and modern ecology.